Appendix 4. Cleaning and sanitising surfaces and utensils. Cleaning. Cleaning and sanitising surfaces and utensils

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1 AUSTRALIA NEW ZEALAND FOOD AUTHORITY SAFE FOOD AUSTRALIA APPENDIX Appendix 4 Cleaning and sanitising surfaces and utensils This appendix includes information on cleaning and sanitising eating and drinking utensils and food contact surfaces. This information is provided for guidance only and businesses are not legally obliged to clean and sanitise at the temperatures and times specified. Cleaning and sanitising are separate procedures, and sanitising is distinct from sterilising. Cleaning in the food industry is a process that removes visible contamination such as food waste, dirt and grease from a surface. This process is usually achieved by the use of water and detergent. During the cleaning process, microorganisms will be removed but the cleaning process is not designed to destroy microorganisms. Sanitising is a process that destroys microorganisms, thereby reducing the numbers of microorganisms present on a surface. This is usually achieved by the use of both heat and water, or by chemicals. Sterilising is a process designed to destroy all microorganisms including microorganisms that have formed a protective coat these protective coats are called spores. Eating and drinking utensils and food contact surfaces do not need to be sterilised. Cleaning and sanitising should usually be done as separate processes. A surface needs to be thoroughly cleaned before it is sanitised as sanitisers are unlikely to be effective in the presence of food residues and detergents. Cleaning The thorough cleaning of eating and drinking utensils and food contact surfaces is a critical step before sanitising for the following reasons: any food residue or other soil left after the cleaning process will protect the bacteria from the sanitation step; any food residue or other soil left after the cleaning process will react with the sanitiser, making the sanitiser less effective against microorganisms; thorough cleaning will physically remove most of the microorganisms present the US National Sanitation Foundation 5 (NSF) reports that dishwashers can remove greater than 99.9% of the bacteria with the removal of food residue and other soil; and the heat used to clean is critical in contributing to the total heat needed to effectively sanitise (by heat) the utensil or food contact surface. 5 The National Sanitation Foundation is a United States organisation founded in It is an independent not-for-profit organisation whose principal functions include standards development and maintenance and third-party certification of products and equipment. Cleaning and sanitising surfaces and utensils AUSTRALIA NEW ZEALAND FOOD STANDARDS CODE CHAPTER 3 (AUSTRALIA ONLY)

2 198 APPENDIX 4 AUSTRALIA NEW ZEALAND FOOD AUTHORITY SAFE FOOD AUSTRALIA A food business must use a cleaning process that ensures the utensil or food contact surface looks clean, feels clean and smells clean. Thorough cleaning can be achieved by: pre-scraping the utensil or surface to remove most of the food residue present; using warm water (see comments below), detergent and agitation to remove food residue; and rinsing the detergent and food residue away. The NSF has found that the temperature of the wash water is extremely significant in providing effective heat-sanitising as the heat accumulated by the utensil during the washing stage contributes to the total heat needed for sanitising. However, the water temperature needed to effectively clean a utensil or surface will depend on the type of food residue to be removed from the utensil or surface. Warm to hot water will be needed for cleaning if grease is to be removed but the temperature should not be so hot that it impedes the cleaning process by baking food residue onto the surface. The NSF found that the best temperature for washing utensils in the food service industry was between 54ºC and 60ºC and that higher temperatures tended to bake food residue on (Mallman et al. 1947). Therefore, if hot water is used to sanitise the utensil or surface, the water temperature for cleaning should not be lower than 54ºC to ensure that enough heat is accumulated during washing for effective sanitising to take place. The detergent used should be appropriate for the task. Ordinary household detergents will usually suffice for manual washing in the food service industry but food manufacturers may need special detergents depending on the food residue to be removed. Mechanical dishwashers need to use detergents that are appropriate to the equipment. Detergents containing sanitisers are not required. If such detergents are used, they are unlikely to be able to clean and sanitise a surface to the standard required. If they are used, a separate sanitising step is still likely to be needed. Advice on whether a detergent that contains a sanitiser can adequately clean and sanitise to the standard required should be sought from the manufacturer or supplier of the product. Agitation to help remove food residue and other soil is either achieved manually through the use of brushes, scourers etc. or mechanically through the use of dish- or glasswashers. Mechanical dishwashers rely on the pressure of the water as well as the overall design of the unit to provide the agitation necessary to remove food residue and other soil. There may be circumstances where cleaning without water is necessary. This is allowable provided the outcome is achieved, that is the utensil or surface is clean to touch and free of extraneous visible matter and objectionable odour. Sanitising Sanitising eating and drinking utensils and food contact surfaces can be achieved through the use of hot water, chemicals or other processes. These are described separately on the following pages. A GUIDE TO THE FOOD SAFETY STANDARDS SECOND EDITION, JANUARY 2001

3 AUSTRALIA NEW ZEALAND FOOD AUTHORITY SAFE FOOD AUSTRALIA APPENDIX Hot water Hot water is the most common method of sanitising eating and drinking utensils and food contact surfaces. Hot water sanitising can be achieved manually or mechanically through the use of a dish- or glasswasher. The temperature needed to destroy infectious diseases present on an eating or drinking utensil or a food contact surface is not clearly indicated in the literature. The NSF has conducted many studies on the use of hot water for sanitising in the food service industry. The first comprehensive studies on mechanical dishwashing processes were sponsored by the NSF and carried out by Dr WL Mallman at Michigan State University. The first research report was published in Further work was carried out and in March 1964 the NSF published a summary report on the study of dishwashing machines. Commercial dishwashers The work of the NSF has been used to specify comprehensive and prescriptive requirements for the manufacture of dishwashers in the US and has also been used by other countries such as Canada. In Australia, the requirements specified in the previous New South Wales Food (General) Regulation (1997) for cleaning and sanitising eating and drinking utensils were based on the NSF studies. The findings of the NSF s work show that sanitising utensils using hot water is complicated and that it is not simply a matter of prescribing a hot water temperature for effective sanitising to be achieved. The main findings of the NSF work can be summarised as follows: thorough cleaning before sanitising is critical to enable effective sanitising to take place; effective sanitising by hot water is achieved by the total heat accumulated by the utensil during the cleaning and rinsing stages of a wash cycle; the volume, pressure and temperature of the water are significant factors for effectively cleaning and sanitising utensils in a dishwashing machine; and the overall design of the dishwashing machine is important in ensuring that all surfaces of the utensils are exposed to the cleaning and rinsing action of the machine for effective cleaning and sanitising to take place. The NSF has produced two standards for dishwashers and glasswashers: 1. NSF Pot, Pan, and Utensil Commercial Spray-Type Washing Machines, NSF International Standard. 2. ANSI/NSF Commercial Spray-Type Dishwashing and Glasswashing Machines, American National Standard/NSF International Standard. Copies of these standards can be purchased from NSF International or from Standards Australia. Cleaning and sanitising surfaces and utensils AUSTRALIA NEW ZEALAND FOOD STANDARDS CODE CHAPTER 3 (AUSTRALIA ONLY)

4 200 APPENDIX 4 AUSTRALIA NEW ZEALAND FOOD AUTHORITY SAFE FOOD AUSTRALIA NSF International 789N Dixboro Road or PO Box Ann Arbor, Michigan USA Standards Australia Sydney Information Centre (inquiries) Phone: Phone: (02) Fax: Fax: (02) info@nsf.org sic@standards.com.au Internet: While the two NSF Standards specify comprehensive criteria for the manufacture of dishwashers and glasswashers, it is not certain whether machines built to these standards remove or destroy all infectious diseases that may be present on a utensil. It is ANZFA s understanding that the studies that were used to develop the design criteria specified in these standards were the studies conducted by the NSF in the 1940s and 1960s. The machines are required to have water temperatures and time cycles that produce a cumulative heat factor that is twice as great as the time temperature standard for pasteurising milk (Bryan & DeHart 1975). The studies did not cover the destruction of food-borne viral pathogens such as hepatitis A as there were no testing methods for these viruses at the time. The most heat-resistant infectious disease that may be transmissible through an eating or drinking utensil appears to be hepatitis A. Hepatitis A is highly resistant to heat and chemicals. The exact temperature necessary to destroy hepatitis A is not known but the Therapeutic Goods Administration in Australia has advised (verbally) that preliminary work being conducted in Germany suggests that a temperature of over 90ºC may be necessary. Sodium hypochlorite can be used to destroy hepatitis A but very high concentrations are needed (5000 ppm or a 1:11 dilution) (Block 1991). Until further studies are conducted on the destruction of hepatitis A, there is no absolute evidence that dishwashers and glasswashers designed to NSF Standards or any other current standards will destroy hepatitis A. However, it should also be noted that there is no evidence either that hepatitis A survives current cleaning and sanitising processes as there have been no known outbreaks (to ANZFA s knowledge) attributed to hepatitis A from cleaned and sanitised eating and drinking utensils. The cleaning and rinsing phases may be effectively removing or diluting the hepatitis A to safe levels and hence destruction may not be necessary. Manufacturers and suppliers of commercial dishwashers need to ensure that the dishwasher achieves the outcomes of this clause, that is, that it so thoroughly cleans and sanitises the utensil that infectious diseases are not transmitted. However, in recognition of the lack of certainty in this area, dishwashers and glasswashers that either meet the NSF Standards or the previous New South Wales regulations are considered to meet the requirements of this clause. Dishwashers and glasswashers that do not meet these requirements may still be used, but the supplier or manufacturer of the machine should provide evidence as to their efficacy. All eating and drinking utensils and food contact surfaces should be thoroughly dry before being reused. If these utensils or surfaces are used while still wet there is a greater chance that any microorganisms remaining on the utensil or surface will be transferred to food or a person s mouth. A GUIDE TO THE FOOD SAFETY STANDARDS SECOND EDITION, JANUARY 2001

5 AUSTRALIA NEW ZEALAND FOOD AUTHORITY SAFE FOOD AUSTRALIA APPENDIX Domestic dishwashers Domestic dishwashers are occasionally used by smaller food businesses that only generate a small volume of dirty eating and drinking utensils. In such situations the installation of a commercial-type dishwasher may not be cost-effective. How effective domestic dishwashers are at cleaning and sanitising is uncertain. However, Bryan and DeHart conducted a study in the US in 1975 to determine whether domestic dishwashers available in the US could meet the same cleaning and sanitising outcome as commercial dishwashers. This study recognised that it is seldom economical or practical to use either commercial dishwashers or hand washing for food service operations in child care centres, family day care, nursing homes and other small food businesses serving food once a day or serving food three times a day to only a few people (Bryan & DeHart 1975). This study concluded that domestic dishwashers that met certain criteria could provide the same cleaning and sanitising outcome as a commercial dishwasher. These criteria were that: (a) dishwashers should have properly functioning temperature-activated sanitising cycles that have to sense a temperature of 65.6ºC or higher before the machine advances to the next step; or (b) dishwashers with either no sanitising cycle or a time-controlled sanitising cycle and forced airflow drying should only be operated with inlet water temperature above 68ºC. Domestic dishwashers that met the above criteria were able to provide an equivalent outcome because, although they operated at lower temperatures, their cycles were much longer about one hour. ANZFA is not aware of any other published studies that have been conducted on the efficacy of domestic dishwashers in terms of the removal and/or destruction of pathogenic microorganisms. It is recommended that further studies be conducted on domestic dishwashers available in Australia, particularly modern models. Until these studies are carried out, domestic dishwashers that meet either criterion (a) or (b) above are permissable. Note that it is not expected that domestic dishwashers would normally be installed in food premises. Most food businesses within the food service sector will need to install commercial dishwashers because of the volume of dirty eating and drinking utensils. Domestic dishwashers that do not meet the above criteria may also be acceptable if the suppliers or manufacturers of the machines provide evidence as to their efficacy. Manually sanitising with hot water Manually sanitising eating and drinking utensils and food contact surfaces is very difficult with hot water. To achieve an adequate level of sanitation, a temperature of 77ºC is likely to be needed and the utensils or surfaces need to be in contact with water at this temperature for at least 30 seconds. A temperature of 77ºC for a period of 30 seconds for manual washing is required in the US Food Code and was also previously specified within the New South Wales Food (General) Regulation To ensure that utensils or food contact surfaces are in contact with hot water at a temperature of 77ºC for 30 seconds, hot water would need to be delivered to a sink at or above 77ºC and the sink would need to have a heating element in it to maintain the temperature of the water at least at 77ºC. Cleaning and sanitising surfaces and utensils AUSTRALIA NEW ZEALAND FOOD STANDARDS CODE CHAPTER 3 (AUSTRALIA ONLY)

6 202 APPENDIX 4 AUSTRALIA NEW ZEALAND FOOD AUTHORITY SAFE FOOD AUSTRALIA However, manually sanitising at this temperature raises occupational health and safety concerns. To avoid burns, rinsing baskets would need to be used to immerse the utensils or equipment, and care would need to be taken to ensure burns did not occur from splashing. While manual sanitising may be able to be carried out at lower temperatures, a longer contact time would be necessary to ensure that an equivalent sanitising outcome was achieved. However, this still requires the sink to contain a heating element to ensure the temperature of the water is maintained at a minimum temperature. Due to the above difficulties, it is recommended that food businesses do not manually sanitise using hot water but instead use dishwashers or chemical sanitisers. Chemicals Chemical sanitisers can be used to sanitise eating and drinking utensils and food contact surfaces. This can be achieved through sanitising manually or by the use of dishwashers that use chemical sanitisers for sanitising instead of hot water. Advice on chemical sanitisers that are suitable for use for eating and drinking utensils and food contact surfaces must be obtained from the supplier or manufacturer of the sanitiser. The supplier or manufacturer should be able to provide information on what the sanitiser can be used for and what the sanitiser can achieve in destroying microorganisms when it is used correctly. Sanitisers will not work correctly if the surface to be sanitised has not been thoroughly cleaned first. If the surface is not clean, the sanitiser will react with the soil left on the surface, reducing the effectiveness of the sanitiser. Food residue and other soil left on a surface will also provide protection to microorganisms. Sanitisers will only work correctly if they are used in the correct concentrations and the instructions are followed. The effectiveness of chemical sanitisers can be directly affected by the temperature, ph, concentration of the sanitiser solution used (too little or too much) and the hardness of the water (US Food Code 1999). Instructions should always be read and followed. If they are not clear, further advice should be sought from the supplier or manufacturer of the chemical. Some of the most commonly used chemical sanitisers in the food industry are chlorinebased compounds. While advice on using chlorine-based sanitisers should be provided when purchasing the sanitiser, the information in the table opposite has been provided for guidance and to illustrate the importance of following instructions when using chemical sanitisers. The table indicates the minimum concentration of a chlorine solution to use, depending on the ph and temperature of the water. After the sanitiser has been applied for the necessary time, the instructions should indicate whether the sanitiser needs to be rinsed off. After the sanitation process is completed, the eating and drinking utensil or food contact surface should be thoroughly dry before it is reused. Air drying is preferable. If towels are used they must be clean and dry. A GUIDE TO THE FOOD SAFETY STANDARDS SECOND EDITION, JANUARY 2001

7 AUSTRALIA NEW ZEALAND FOOD AUTHORITY SAFE FOOD AUSTRALIA APPENDIX Minimum temperature ( C) Minimum temperature ( C) Minimum concentration for water at for water at (mg/l or ppm) ph 10 or less ph 8 or less Source: US Food Code Other processes Processes other than heat and chemicals may be used to sanitise eating and drinking utensils and food contact surfaces, for example dry steam cleaning and ultraviolet radiation. Technological advances are also being made in this area and other processes, such as irradiation, pulsed electric fields and microwaves, may be able to be used successfully in the future. Cleaning and sanitising surfaces and utensils AUSTRALIA NEW ZEALAND FOOD STANDARDS CODE CHAPTER 3 (AUSTRALIA ONLY)

8 204 AUSTRALIA NEW ZEALAND FOOD AUTHORITY SAFE FOOD AUSTRALIA A GUIDE TO THE FOOD SAFETY STANDARDS SECOND EDITION, JANUARY 2001